The concept of a superconducting flux pump is relatively straightforward. A small magnetic field repeatedly applied will lead to a much larger field being trapped within the superconductor. This field is limited by the volume of the superconductor and by its critical current but not by the excitation field. As long as the superconductor is kept cold the field will persist without the need for an externally applied current.
Here we will describe new techniques which, in embodiments, facilitate creation of high magnetic fields, for example in the range of 1 Tesla and greater. Furthermore, in embodiments the magnetisation may be substantially perpendicular to an essentially planar magnet. In still other embodiments the magnets may be magnetised in a range of desired field patterns, optionally varying in both time and space, for example, to create a uniform field or a travelling wave field.
In broad terms embodiments of the techniques we describe employ a medium, typically a superconductor, to “store” the magnetic field. Actuation of the medium so that it is magnetic is, in embodiments, provided by materials which can change their magnetic state, for example, going from paramagnetic to either ferromagnetic or diamagnetic. When they change their magnetic states then the change in magnetic field induces currents in the superconductor, magnetising (or de-magnetising) the superconductor. Embodiments of the techniques we describe, for example, embodiments of the geometry and/or methods described, have a very wide range of potential applications.